Oh, yeah, yours is very likely a CB300, with the C standing for the (primarily) commercial cut-away chassis. Other than the body, and possibly some heavier duty components, the B300 and CB300 are essentially identical.
As has been described in this thread, the only way to know for sure is to find the chassis VIN, versus the registration VIN. (The chassis VIN can also be decoded to identify which engine was original equipment.)
Likewise, the exact size and version of the engine is stamped (not cast) into the block, usually immediately below one of the heads.
